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Semiconductor Fabrication

IP.com Disclosure Number: IPCOM000098435D
Original Publication Date: 1960-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Mutter, WE: AUTHOR

Abstract

In alloying a thin metal film having a thickness within the range of 0. 005 to 1.0 mil to a semiconductor wafer, there is a problem of the film melting and separating into a plurality of discrete balls of different sizes. This occurs because the surface tension of the liquid metal film exceeds the interfacial tension between the liquid and the solid semiconductor substrate. When the unit cools, the resulting terminal or alloy junction has inferior electrical properties.

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Semiconductor Fabrication

In alloying a thin metal film having a thickness within the range of 0. 005 to
1.0 mil to a semiconductor wafer, there is a problem of the film melting and separating into a plurality of discrete balls of different sizes. This occurs because the surface tension of the liquid metal film exceeds the interfacial tension between the liquid and the solid semiconductor substrate. When the unit cools, the resulting terminal or alloy junction has inferior electrical properties.

To overcome this problem, a thin metal film 10 is applied to a zone 11 of a semiconductor body 12 as by vacuum evaporation. Then a continuous coherent film 13 of silicon monoxide is deposited over the film 10 and a portion of the surface of zone 11 by evaporation through an apertured mask 14. Then the mask is removed and the unit shown in the middle drawing is introduced into an alloying furnace. The thin metal film 10 alloys with the zone 11 as shown in the lower drawing. During alloying, the silicon monoxide film 13 serves as a tough restraining cover which resists surface tension forces created when the film 10 becomes molten, thus preventing balling. The alloy penetration into the semiconductor zone 11 is uniform over the entire area of the metal film.

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